JP2002235993A - Spiral fin tube and refrigeration air conditioning device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a shape allowing heat exchange to be performed efficiently concerning a spiral fin tube. SOLUTION: A spiral fin tube is provided with a heat transfer tube 22 that has refrigerant circulating inside and is meandered, and fins 21 that are spirally wound about the heat transfer tube 22 in such a manner that the pitch of the fins 21 becomes gradually nondense from the refrigerant inflow side to the refrigerant outflow side.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a spiral fin tube type heat exchanger in a refrigeration / air-conditioning apparatus such as a refrigerator or a low-temperature showcase, and a refrigeration / air-conditioning apparatus provided with such a heat exchanger.

[0002]

2. Description of the Related Art In recent years, in a refrigerator or the like of a refrigerator, the problem of clogging due to dust between air inflow fins has been solved.
Spiral fin tube types are often used because they are more advantageous than ordinary plate fin tube type heat exchangers. As a condenser of this kind of spiral fin tube, there is a condenser as disclosed in JP-A-2000-310473.

An example of the above-mentioned conventional spiral fin tube condenser for refrigerator will be described with reference to the drawings.

FIG. 7 is a cross-sectional plan view of a main part showing the structure of a conventional refrigerator. As shown in the figure, a spiral fin tube 10 of a condenser is installed. In this spiral fin tube 10, the pitch of the fins 11 is uniformly wound, and the fin width is also uniform.

Generally, in the condenser having the above-described structure, the refrigerant flows with the leeward side as the refrigerant inflow side and the leeward side as the refrigerant outflow side in order to maintain the temperature difference between the wind whose temperature rises due to heat exchange and the radiating refrigerant. Improves heat dissipation efficiency.

[0006]

However, in the above configuration, when the outer surface area between the fin and the heat transfer tube is not sufficiently large, or when the heat transfer coefficient on the air side is small, the heat transfer tube is not provided. Irrespective of the increase or decrease in the heat transfer coefficient on the inside, that is, on the refrigerant side, the heat transfer amount inside and outside the heat transfer tube is governed by the heat transfer amount on the air side, and heat cannot be exchanged efficiently.

In general, the refrigerant flows in the gas phase on the refrigerant inflow side, so that the flow velocity is high, the refrigerant liquefied by heat exchange gradually decreases in flow velocity, and the flow velocity decreases on the refrigerant outflow side. Although it is difficult to predict by gas and liquid and their flow patterns, in a single-phase region of gas and liquid, as the flow rate of the refrigerant increases, the heat transfer coefficient increases accordingly. As for the heat transfer coefficient at the time of condensation, the heat transfer coefficient tends to increase at a stretch from the saturation temperature at which condensation starts at the refrigerant inlet, and to decrease as the condensation proceeds. That is, the heat transfer coefficient in the heat transfer tube rises near the refrigerant inlet, then gradually decreases toward the outlet, and becomes constant when the condensation ends.

The reciprocal of the combined heat transfer coefficient of the spiral fin tube from the refrigerant to the air is the reciprocal of the product of the heat transfer coefficient on the inner surface of the heat transfer tube and the heat transfer area, the heat transfer coefficient on the outer side of the heat transfer tube and the transfer coefficient. It is shown as the sum of the product of the thermal area and the reciprocal.

Considering the combined heat transfer coefficient from the refrigerant to the air at a part of the refrigerant inflow side, the inside of the heat transfer tube has a high flow rate of the refrigerant and a large heat transfer coefficient. The heat transfer coefficient is further increased. That is, the reciprocal of the product of the heat transfer coefficient and the internal area of the heat transfer tube becomes smaller on the inner surface on the refrigerant inflow side. Next, on the outside of the heat transfer tube, the reciprocal of the product of the heat transfer coefficient to air and the outer surface area of the heat transfer tube including the fins does not change because the flow is not related to the refrigerant flow. Therefore, the combined heat transfer coefficient on the inflow side is the sum of the respective reciprocals, but the change due to the increased heat transfer coefficient on the heat transfer tube inner surface side does not change the heat transfer tube outside, that is, the air side,
The degree of change in the combined heat transfer coefficient, which is the sum of the reciprocals, is small.

That is, when the outer surface area of the fins and the heat transfer tube is not sufficiently large, or when the heat transfer coefficient on the air side is small, the heat transfer coefficient inside the heat transfer tube, that is, on the refrigerant side is increased. Regardless, the combined heat transfer coefficient is not large enough to allow efficient heat exchange.

When the fin pitch is reduced for the purpose of increasing the outer surface area, the flow of air is obstructed, the ventilation resistance is increased, and the performance is reduced.

SUMMARY OF THE INVENTION The present invention solves the conventional problem, in which the outer surface area or the heat transfer coefficient of a finned heat transfer tube is changed according to the heat transfer amount of the refrigerant flowing inside the heat transfer tube. An object of the present invention is to provide a spiral fin tube capable of efficiently performing heat exchange.
It is another object of the present invention to provide a refrigeration / air-conditioning apparatus having high energy efficiency by using the spiral fin tube thus improved.

[0013]

SUMMARY OF THE INVENTION In order to achieve the above object, the present invention provides a heat transfer tube in which a refrigerant flows and is bent in a meandering shape, and is wound spirally around the heat transfer tube. In a spiral fin tube provided with fins, the pitch of the fins is gradually reduced from the refrigerant inflow side to the refrigerant outflow side. Thereby, on the inflow side where the heat transfer amount of the refrigerant is large, the fin pitch is reduced,
The outer surface area of the heat transfer tube is increased, and the heat transfer coefficient inside and outside the tube is increased on both sides, so that heat can be exchanged efficiently. Also, the fin pitch becomes sparser as the heat transfer amount of the refrigerant decreases,
The ventilation resistance can be reduced while performing sufficient heat exchange.

The present invention also provides a spiral fin tube having a heat transfer tube in which a refrigerant flows and bent in a meandering shape, and a fin wound in a spiral shape around the heat transfer tube. Is gradually reduced from the refrigerant inflow side to the refrigerant outflow side for each row of the heat transfer tubes. As a result, on the inflow side where the amount of heat transfer of the refrigerant is large, the fin pitch is packed, the outer surface area of the tube is increased, and heat can be exchanged efficiently. The ventilation resistance can be reduced while performing sufficient heat exchange. Since the fin pitch does not change continuously, the processing method can be relatively simplified.

Further, according to the present invention, there is provided a spiral fin tube having a heat transfer tube in which a refrigerant flows and bent in a meandering shape, and a fin wound in a spiral shape around the heat transfer tube. Is gradually narrowed from the refrigerant inflow side to the refrigerant outflow side. Thereby, on the inflow side where the heat transfer amount of the refrigerant is large, the fin width is increased,
The outer surface area of the heat transfer tube is increased, and the heat transfer coefficient inside and outside the tube is increased on both sides, so that heat can be exchanged efficiently. Further, the fin width becomes narrower as the heat transfer amount of the refrigerant decreases, and the ventilation resistance can be reduced while performing sufficient heat exchange.

Further, according to the present invention, there is provided a spiral fin tube having a heat transfer tube in which a refrigerant flows and bent in a meandering shape, and a fin wound spirally around the heat transfer tube. Is gradually narrowed from the refrigerant inflow side to the refrigerant outflow side for each row of the heat transfer tubes. As a result, on the inflow side where the amount of heat transfer of the refrigerant is large, the fin width is increased, the outer surface area of the tube is increased, heat can be exchanged efficiently, and as the heat transfer amount of the refrigerant decreases, the fin width decreases in each row. The ventilation resistance can be reduced while performing sufficient heat exchange. Since the fin width does not change continuously, the processing method can be relatively simplified.

The present invention also provides a spiral fin tube comprising a heat transfer tube in which a refrigerant flows and bent in a meandering shape, and a fin wound spirally around the heat transfer tube. The air path in which the tubes were installed was gradually widened from the refrigerant inflow side to the refrigerant outflow side. Thereby, on the inflow side where the heat transfer amount of the refrigerant is large, since the air path is narrow, the wind speed is increased, the heat transfer coefficient outside the tube increases, and the heat transfer coefficient inside and outside the tube increases on both sides. Heat can be exchanged efficiently. Further, as the heat transfer amount of the refrigerant decreases, the air path becomes wider and the wind speed decreases, but the ventilation resistance can be reduced while performing sufficient heat exchange.

[0018]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Embodiments of the present invention will be described below with reference to FIGS.

(Embodiment 1) A spiral fin tube according to Embodiment 1 of the present invention will be described with reference to the drawings.

FIG. 1 is a cross-sectional plan view of a main part showing a structure of a condenser of a spiral fin tube according to Embodiment 1 of the present invention. In FIG. 1, reference numeral 21 denotes a spiral fin formed by spirally winding a strip-shaped thin plate around a heat transfer tube described later. Reference numeral 22 denotes a known heat transfer tube which is formed in a serpentine shape and on which the spiral fin 21 is wound. Thus, the spiral fins 21 are wound tightly on the A side in FIG. 1 and are sparsely wound toward the B side. A side is connected to a refrigerant inflow side of a refrigeration cycle (not shown), and B side is connected to a refrigerant outflow side.

The operation of the spiral fin tube configured as described above will be described below.

The refrigerant flows in from the A side in FIG. 1, passes through the heat transfer tube 22, and flows out to the B side. At this time, since it is a condenser, the refrigerant entering from the A side is in a gas state. And while releasing heat outside the heat transfer tube 22,
B gradually changes from gas state to liquid state and flows out
On the side, it is in a liquid state. FIG. 2 shows the heat transfer coefficient inside the heat transfer tube 22 at this time. This is a rough value obtained by experiments and numerical simulations. When the refrigerant entering from the inflow side reaches the saturation temperature at which condensation starts, the heat transfer coefficient increases at a stretch, then gradually decreases until the condensation ends, and when the refrigerant is in a liquid state, the heat transfer coefficient is stabilized. I do. Accordingly, since the surface area inside the heat transfer tube 22 is constant, the heat transfer amount gradually decreases from the side A to the side B.

As described above, the fins 21 become sparser from the side A to the side B. Therefore, the heat transfer tube 2
2, the surface area on the air side is large on the A side and is reduced toward the B side. That is, the heat transfer tube 22
The heat transfer amount on the air side is larger on the A side and smaller on the B side. By making it the same as the heat transfer amount of the refrigerant inside the heat transfer tube 22, the A side can sufficiently exchange heat, and the B side can secure a necessary and sufficient heat exchange amount,
The fin pitch can be reduced, and the ventilation resistance can be reduced.

That is, it is possible to provide a spiral fin tube condenser that performs more efficient heat exchange as well as reducing material costs. In FIG. 1, the fin 21 is provided at the bent portion of the spiral fin tube.
You don't have to. Although the spiral fin tubes in the figure have the same length in the horizontal direction, they may be different. Although the fin pitch is sparsely changed over the entire spiral fin tube, the fin pitch only on the side near the refrigerant outflow side may be made sparse, and the fin pitch only on the side near the refrigerant inflow side may be reduced. It may be dense.

(Embodiment 2) A spiral fin tube according to Embodiment 2 of the present invention will be described with reference to FIG.

In FIG. 3, reference numeral 31 denotes a spiral fin which is spirally wound around the heat transfer tube 22. In the present embodiment, the spiral fin 31 is wound tightly on the A side, and is sparsely wound on each row toward the B side, but the other configuration is the same as that of the first embodiment. .

The operation of the spiral fin tube configured as described above will be described below.

The refrigerant flows in from the A side in FIG. 3, passes through the heat transfer tube 22, and flows out to the B side. At this time, since it is a condenser, the refrigerant entering from the A side is in a gas state. And while releasing heat outside the heat transfer tube 22,
B gradually changes from gas state to liquid state and flows out
On the side, it is in a liquid state. FIG. 2 shows the heat transfer coefficient inside the heat transfer tube 22 at this time. This is a rough value obtained by experiments and numerical simulations. When the refrigerant entering from the inflow side reaches the saturation temperature at which condensation starts, the heat transfer coefficient increases at a stretch, then gradually decreases until the condensation ends, and when the refrigerant becomes a liquid state, the heat transfer coefficient becomes constant. I do. Therefore, since the inner surface area of the heat transfer tube 22 is constant, the heat transfer amount gradually decreases from the A side to the B side.

As described above, the fins 31 are sparser in each row from the side A to the side B. Therefore, the surface area of the heat transfer tube 22 on the air side is made larger on the A side, and becomes smaller for each row as it goes to the B side. In other words, the heat transfer amount on the air side of the heat transfer tube 22 is large on the A side, and becomes smaller for each row toward the B side. By making it the same as the heat transfer amount of the refrigerant inside the heat transfer tube 22,
The heat exchange can be sufficiently performed on the A side, and the fin pitch can be reduced and the ventilation resistance can be reduced while securing the necessary and sufficient heat exchange amount on the B side. Further, since the fin pitch is changed for each row, the processing can be relatively simplified.

That is, it is possible to provide a spiral fin tube condenser that performs more efficient heat exchange as well as reducing material costs. In FIG. 3, the fin 31 is provided at the bent portion of the spiral fin tube.
You don't have to. Although the lengths in the horizontal direction in the figure are uniform, they may be different. Also, the fin pitch is sparsely changed over the entire spiral fin tube, but the fin pitch only on the side near the refrigerant outflow side may be made sparse, and the fin pitch only on the side near the refrigerant inflow side may be reduced. It may be dense.

(Embodiment 3) A spiral fin tube according to Embodiment 3 of the present invention will be described with reference to FIG.

FIG. 4 is a cross-sectional plan view of a main part showing a structure of a condenser of a spiral fin tube according to Embodiment 3 of the present invention. In the figure, reference numeral 41 denotes a spiral fin, which is wound around the heat transfer tube 22 such that the fin width on the A side is the largest and decreases toward the B side. Other configurations are the same as those of the first and second embodiments, and thus description thereof is omitted.

The operation of the spiral fin tube configured as described above will be described below.

The refrigerant flows in from the A side in FIG. 4, passes through the heat transfer tube 22, and flows out to the B side. At this time, since it is a condenser, the refrigerant entering from the A side is in a gas state. And while releasing heat outside the heat transfer tube 22,
B gradually changes from gas state to liquid state and flows out
On the side, it is in a liquid state. FIG. 2 shows the heat transfer coefficient inside the heat transfer tube 22 at this time. This is a rough value obtained by experiments and numerical simulations. When the refrigerant entering from the inflow side reaches the saturation temperature at which condensation starts, the heat transfer coefficient increases at a stretch, then gradually decreases until the condensation ends, and when the refrigerant is in a liquid state, the heat transfer coefficient is stabilized. I do. Accordingly, since the surface area inside the heat transfer tube 22 is constant, the heat transfer amount gradually decreases from the side A to the side B.

Here, the width of the fin 41 decreases from the side A to the side B. This is heat transfer tube 2
2, the surface area on the air side is increased on the A side, and is reduced toward the B side. In other words, the heat transfer amount on the air side of the heat transfer tube 22 is larger on the A side and smaller on the B side. By making the heat transfer amount the same as that of the refrigerant inside the heat transfer tube 22, the heat exchange can be sufficiently performed on the side A and the fin width can be reduced while ensuring the necessary and sufficient heat exchange amount on the side B. Resistance can be reduced.

That is, it is possible to provide a spiral fin tube condenser that performs more efficient heat exchange as well as reducing material costs. In FIG. 4, the fin 41 is provided at the bent portion of the spiral fin tube.
You don't have to. Although the lengths in the horizontal direction in the figure are uniform, they may be different. Although the fin width is reduced over the entire spiral fin tube, the fin width only on the side near the refrigerant outflow side may be reduced, or the fin width only on the side near the refrigerant inflow side is increased. May be.

(Embodiment 4) A spiral fin tube according to Embodiment 4 of the present invention will be described with reference to FIG.

FIG. 5 is a cross-sectional plan view of a main part showing a structure of a condenser of a spiral fin tube according to Embodiment 4 of the present invention. In the figure, reference numeral 51 denotes a spiral fin, which is wound around the heat transfer tube 22 such that the width of the fin in the row on the A side is the largest and becomes smaller as it goes toward the row on the B side. Other configurations are the same as those described above.

The operation of the spiral fin tube configured as described above will be described below.

The refrigerant flows in from the A side in FIG. 5, passes through the heat transfer tube 2, and flows out to the B side. At this time, since it is a condenser, the refrigerant entering from the A side is in a gas state. Then, while releasing heat to the outside of the heat transfer tube, the state gradually changes from the gas state to the liquid state, and the outflow side B becomes the liquid state. FIG. 2 shows the heat transfer coefficient inside the heat transfer tube 22 at this time. This is a rough value obtained by experiments and numerical simulations. When the refrigerant entering from the inflow side reaches the saturation temperature at which condensation starts, the heat transfer coefficient increases at a stretch, then gradually decreases until the condensation ends, and when the refrigerant becomes a liquid state, the heat transfer coefficient becomes constant. I do. Accordingly, since the surface area inside the heat transfer tube 22 is constant, the heat transfer amount gradually decreases from the side A to the side B.

Here, the width of the fins 51 decreases from row A to row B in each row. This is so that the surface area of the heat transfer tube 22 on the air side is large on the A side and is reduced toward the B side. In other words, the heat transfer amount on the air side of the heat transfer tube 22 is large on the A side, and decreases for each row as it goes to the B side. Heat transfer tube 2
2 By making the heat transfer amount the same as that of the refrigerant inside, heat exchange can be sufficiently performed on the A side, and the fin width is reduced and the ventilation resistance is reduced while securing the necessary and sufficient heat exchange amount on the B side. can do. Further, since the fin width is changed for each row, the processing can be relatively simplified. That is, it is possible to provide a spiral fin tube condenser that performs more efficient heat exchange as well as reducing material costs. In FIG. 5, the fins 51 are provided at the bent portions of the spiral fin tube, but need not be provided. Although the lengths in the horizontal direction in the figure are uniform, they may be different.
Although the fin width is reduced over the entire spiral fin tube, the fin width only on the side near the refrigerant outflow side may be reduced, or the fin width only on the side near the refrigerant inflow side is increased. May be.

(Embodiment 5) A spiral fin tube according to Embodiment 5 of the present invention will be described with reference to FIG.

FIG. 6 is a cross-sectional plan view of a main part showing a structure of a spiral fin tube condenser according to Embodiment 5 of the present invention. In the figure, reference numeral 61 denotes a spiral fin wound around a heat transfer tube 22 'described later at an equal pitch. Reference numeral 22 'denotes an electric heating tube formed in a serpentine shape, having a straight pipe portion having the shortest length on the A side, and expanding toward the B side. Numeral 63 denotes a duct forming an air passage, which is provided in a machine room such as a refrigerator. Thus, the duct 63 has a shape corresponding to the shape of the spiral fin tube, and is configured such that the opening width on the air inflow side is the largest and becomes smaller toward the outlet side. At the outlet side, the refrigerant outlet side is positioned on the air inflow side, and is mounted in the duct 63 by an appropriate method.

The operation of the spiral fin tube configured as described above will be described below.

The refrigerant flows in from the A side in FIG. 6, passes through the heat transfer tube 22, and flows out to the B side. At this time, since it is a condenser, the refrigerant entering from the A side is in a gas state. And while releasing heat outside the heat transfer tube 22,
B gradually changes from gas state to liquid state and flows out
On the side, it is in a liquid state. FIG. 2 shows the heat transfer coefficient inside the heat transfer tube 22 at this time. This is a rough value obtained by experiments and numerical simulations. When the refrigerant entering from the inflow side reaches the saturation temperature at which condensation starts, the heat transfer coefficient increases at a stretch, then gradually decreases until the condensation ends, and when the refrigerant becomes a liquid state, the heat transfer coefficient becomes constant. I do. Accordingly, since the surface area inside the heat transfer tube 22 is constant, the heat transfer amount gradually decreases from the side A to the side B.

Here, the duct 63 is gradually narrowed with respect to the flow of the wind. That is, the wind speed increases as going from the windward side to the leeward side. The wind speed of the spiral fin tube decreases as going from side A to side B. Since the heat transfer coefficient on the outside of the heat transfer tube 22 increases in proportion to the wind speed of the air, the wind speed of the heat transfer tube 22 is increased on the A side, and decreases on the B side. In other words, the heat transfer amount on the air side of the heat transfer tube 22 is larger on the A side and smaller on the B side. By making the heat transfer amount the same as that of the refrigerant inside the heat transfer tube 22, the A side can sufficiently exchange heat, and the B side can secure a necessary and sufficient amount of heat exchange.

That is, by matching the duct shape to a fan or the like having a small suction area, it is possible to provide a spiral fin tube condenser that performs more efficient heat exchange. In FIG. 6, the fin 61 is provided at the bent portion of the spiral fin tube, but need not be provided. FIG.
Although the width of the duct 63 is gradually changed in the horizontal direction, the same effect can be obtained by gradually changing the shape of the duct in the vertical direction with respect to the drawing of the spiral fin tube. Although the duct 63 is reduced over the entire spiral fin tube, the duct width only on the leeward side near the refrigerant outflow side may be reduced, or the duct only on the leeward side near the refrigerant inflow side. The width may be increased.

[0048]

As described above, according to the first aspect of the present invention, a heat transfer tube in which a refrigerant flows and is bent in a meandering shape is provided.
In a spiral fin tube provided with spirally wound fins around the heat transfer tube, the pitch of the fins is gradually reduced from the refrigerant inflow side to the refrigerant outflow side. As a result, on the inflow side where the heat transfer amount of the refrigerant is large, the fin pitch is reduced, the outer surface area of the heat transfer tube is increased, and the heat transfer coefficient inside and outside the tube is increased, so that heat can be exchanged efficiently. . In addition, the fin pitch becomes sparser as the heat transfer amount of the refrigerant decreases, and the ventilation resistance can be reduced while performing sufficient heat exchange.

According to a second aspect of the present invention, there is provided a spiral fin tube including a heat transfer tube in which a refrigerant flows and bent in a meandering shape, and a fin wound in a spiral shape around the heat transfer tube. The pitch of the fins is gradually reduced from the refrigerant inflow side to the refrigerant outflow side for each row of the heat transfer tubes. As a result, on the inflow side where the amount of heat transfer of the refrigerant is large, the fin pitch is packed, the outer surface area of the tube is increased, and heat can be exchanged efficiently. The ventilation resistance can be reduced while performing sufficient heat exchange. Since the fin pitch does not change continuously, the processing method can be relatively simplified.

According to a third aspect of the present invention, there is provided a spiral fin tube including a heat transfer tube in which a refrigerant flows and bent in a meandering shape, and a fin wound in a spiral shape around the heat transfer tube. The width of the fin is gradually reduced from the refrigerant inflow side to the refrigerant outflow side. Thereby, on the inflow side where the amount of heat transfer of the refrigerant is large, the fin width is widened, the outer surface area of the heat transfer tube is increased, and the heat transfer coefficient inside and outside the tube is increased in both directions, so that heat can be exchanged efficiently. . Further, the fin width becomes narrower as the heat transfer amount of the refrigerant decreases, and the ventilation resistance can be reduced while performing sufficient heat exchange.

According to a fourth aspect of the present invention, there is provided a spiral fin tube having a heat transfer tube in which a refrigerant flows and bent in a meandering shape, and a fin wound in a spiral shape around the heat transfer tube. The width of the fin is gradually reduced from the refrigerant inflow side to the refrigerant outflow side for each row of the heat transfer tubes. As a result, on the inflow side where the heat transfer amount of the refrigerant is large, the fin width is increased, the outer surface area of the tube is increased, heat can be exchanged efficiently, and as the heat transfer amount of the refrigerant decreases, the fin width decreases in each row. The ventilation resistance can be reduced while performing sufficient heat exchange. Since the fin width does not change continuously, the processing method can be relatively simplified.

According to a fifth aspect of the present invention, there is provided a spiral fin tube having a heat transfer tube in which a refrigerant flows and bent in a meandering shape, and a fin wound in a spiral shape around the heat transfer tube. The air passage in which the spiral fin tube is installed is gradually widened from the refrigerant inflow side to the refrigerant outflow side. Thereby, on the inflow side where the heat transfer amount of the refrigerant is large, since the air path is narrow, the wind speed is increased, the heat transfer coefficient outside the tube increases, and the heat transfer coefficient inside and outside the tube increases on both sides. Heat can be exchanged efficiently. Further, as the heat transfer amount of the refrigerant decreases, the air path becomes wider and the wind speed decreases, but the ventilation resistance can be reduced while performing sufficient heat exchange.

The invention according to claims 7 and 8 is a refrigeration / air-conditioning apparatus provided with the above-mentioned fin tubes, which improves the operation efficiency and achieves an energy saving effect.

[Brief description of the drawings]

FIG. 1 is a cross-sectional plan view of a spiral fin tube according to a first embodiment of the present invention.

FIG. 2 is a characteristic diagram of the heat transfer coefficient on the inner surface of the heat transfer tube.

FIG. 3 is a cross-sectional plan view of a spiral fin tube according to a second embodiment of the present invention.

FIG. 4 is a cross-sectional plan view of a spiral fin tube according to a third embodiment of the present invention.

FIG. 5 is a cross-sectional plan view of a spiral fin tube according to a fourth embodiment of the present invention.

FIG. 6 is a cross-sectional plan view of Embodiment 5 of the spiral fin tube according to the present invention.

FIG. 7 is a cross-sectional plan view of a conventional spiral fin tube.

[Explanation of symbols]

 Reference Signs 21 fin 31 fin 41 fin 51 fin 61 fin 22 heat transfer tube 22 ′ heat transfer tube

 ──────────────────────────────────────────────────続 き Continued on the front page (72) Inventor Hiroaki Kase 4-5-2-5 Takaida Hondori, Higashiosaka-shi, Osaka Matsushita Refrigerator Co., Ltd. F-term (reference) 3L103 AA17 AA37 BB44 CC22 CC30 DD06 DD33

Claims (8)

[Claims] 1. A spiral fin tube including a heat transfer tube in which a refrigerant flows and bent in a meandering shape, and a fin wound in a spiral shape around the heat transfer tube, wherein the pitch of the fins is A spiral fin tube which is gradually sparse from a refrigerant inflow side to a refrigerant outflow side. 2. A spiral fin tube having a heat transfer tube in which a refrigerant flows and bent in a meandering shape, and a fin wound in a spiral shape around the heat transfer tube, wherein the pitch of the fins is A spiral fin tube wherein the heat transfer tubes are gradually sparsely arranged from a refrigerant inflow side to a refrigerant outflow side for each row. 3. A spiral fin tube including a heat transfer tube in which a refrigerant flows and bent in a meandering shape, and a fin wound in a spiral shape around the heat transfer tube. A spiral fin tube having a width gradually reduced from a refrigerant inflow side to a refrigerant outflow side. 4. A spiral fin tube including a heat transfer tube in which a refrigerant flows and bent in a meandering shape, and a fin wound in a spiral shape around the heat transfer tube, wherein the width of the fin is: A spiral fin tube characterized by gradually narrowing from a refrigerant inflow side to a refrigerant outflow side for each row of heat transfer tubes. 5. A spiral fin tube including a heat transfer tube in which a refrigerant flows and bent in a meandering shape, and a spiral fin tube having a spirally wound fin around the heat transfer tube. A spiral fin tube, wherein the thickness of the spiral fin tube is gradually reduced from the refrigerant inflow side to the refrigerant outflow side for each row of the heat transfer tubes. 6. A heat transfer tube, comprising: a heat transfer tube in which a refrigerant flows and bent in a meandering shape; and a spiral fin tube having a fin wound in a spiral shape around the heat transfer tube. A spiral fin tube wherein the length of the portion is gradually increased from the refrigerant inflow side to the refrigerant outflow side. 7. A refrigeration / air-conditioning apparatus comprising the spiral fin tube according to claim 1 in a heat exchange section with air. 8. A refrigerating and air-conditioning apparatus comprising a duct which is formed gradually wider from a refrigerant inflow side to a refrigerant outflow side and in which a spiral fin tube is installed, and wherein the spiral fin tube according to claim 6 is provided in the duct.